ADC.setup() Prevents Python Program from Running at Autostart

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#1

I am trying to write a program that reads the analog values of a sonar on the Beaglebone Black Wireless (Debian image 2017-07-01). The program runs fine if executed from the command line, but when I try to run it automatically at startup (using crontab), the program doesn’t run at all (as indicated by a grep command). Here is the relevant code:

from time import sleep
import Adafruit_BBIO.ADC as ADC
ADC.setup()

while True:
    sonar = ADC.read(pin)
    print sonar
    sleep(.5)

Any help in this matter would be greatly appreciated.

#2

Check out this example of how to run a script at startup:
https://github.com/adafruit/adafruit-beaglebone-io-python/blob/master/doc/run_config-pin_during_startup.md

#3

On Tue, 12 Sep 2017 12:43:26 -0500, Drew Fustini
<pdp7pdp7@gmail.com> declaimed the following:

Check out this example of how to run a script at startup:
https://github.com/adafruit/adafruit-beaglebone-io-python/blob/master/doc/run_config-pin_during_startup.md

from time import sleep
import Adafruit_BBIO.ADC as ADC
ADC.setup()
while True:
    sonar = ADC.read(pin)
    print sonar

  I'd be concerned about that print statement... Where is stdout going
for a cron job?

#4

I’m assuming you mean how I’m displaying the values. I’m not, but disabling the print statement didn’t fix the problem.

#5

Cron jobs aren't supposed to have output. If they do, it's mailed to the
owner of the job, presumably because they contain error messages for
debugging.

#6

Hello,

Run the CRON job with EDITOR=nano crontab -e and make sure you are root. I forget what it must take to become root in our new systems. By default, the Debian Stretch Distro does not place us in the root directory. sudo -i will do it!

Seth

#7

Oh and Medina,

You may need to set up all your code and software in the root folder to allow for direct action in your boot.

Seth

P.S. sudo -i

#8

Hello Medina,

Seth here, again. Oh and dude, you can also throw all that software into the Autorun folder on Cloud 9.

Seth

P.S. Just a reminder…if you use sudo -i, you can exit out by just typing exit. That will bring you to your debian@… or whatever your name is now. You would, before the exit cmd, be root@… and not debian@… or so on.

#9

All my files are already in root. I disabled the security in my Beaglebone so I can log in with root and have administrative privileges by default. I already tried crontab and it didn’t run. I prefer not to use Cloud9 due to its limitations. That being said, uploading a file to the autorun folder didn’t work either.

#10

Okay…no issue. I hope things work out. If I come across the correct way to start a program/software on boot, I will let you know.

Seth

P.S. I read about it a while back but I came up empty with my current search. They have some Debian docs. on it. I will let you know if I come across it again.

#11

Hello Tomas,

I just listened to Fustini in this post, https://github.com/adafruit/adafruit-beaglebone-io-python/blob/master/doc/run_config-pin_during_startup.md, by starting a service and making two uart pins available to me on boot.

Seth

P.S. I hope things are going well in your quest. BBB!